1. Field of the Invention
The present invention relates to an improvement in a contact-free sealing member used for sealing an isolated chamber, into which a material such as plastic film tape is continuously fed at a high speed.
2. Description of the Prior Art
In a winding apparatus a tape is continuously wound by a winding reel at a high speed. When the winding speed exceeds a certain level, the air surrounding the tape is successively sucked in a narrow space between a roll of the wound tape at the winding reel and a part of the tape to be wound. As a result of the air suction, the tape receives a floating force caused by an unstable compressed air film due to wedge action or squeeze action effect. In addition, the feeding tape is also subjected to an irregular external force such as variations of the tape tension arising from the eccentric rotation of the reel and/or mechanical vibrations of mechanical portions in the winding apparatus. As a result of such an irregular force, the tape vibrates in the widthwise direction thereof and accordingly there arises irregularities of winding, i.e., uneven winding of the side portions of the tape. For example, in the case of the tape of 1/2 inch width this winding trouble appears when it is wound at a speed more than 5-6 m/sec. When the tape is unevenly wound, not only the appearance of the wound tape becomes indecent, but also the tape gets curly. Therefore, the tape becomes liable to be damaged and further the feeding operation of the tape becomes unstable when it is used for playback.